"Classic" strains of streptococci, purported to be either of "Group H", or Streptococcus sanguis, can be grouped by combinations of attributes that include antigenic composition, serologic reactivities with selected "standard" test sera, sensitivity to a cell wall lysin, phage adsorption presence of cell wall fimbriae, and the presence and amounts of cell wall sugars. The validity and utility of the groupings will be extended by a broader use of certain tests on the reference strains, and by the testing of a larger number of strains from other collections as well as from recent isolates.